This invention concerns a double-oblique-toothed two-stage spur wheel drive. This drive comprises a first pinion consisting of gearwheel halves that are coupled by way of an intermediate wheel composed also of respective gearwheel halves, with respective gearwheel halves of a first toothed wheel in a first stage of the drive. The first toothed wheel is coupled with a second pinion which meshes with a second toothed wheel in a second stage of the drive.
In one known such drive, which will be described in further detail with reference to certain figures of the drawings, the arrangement of the first pinion, the intermediate wheel and the first toothed wheel in the first gear is essentially such that the spacing between the axes of the first pinion and the first toothed wheel is greater than the sum of the radii of the said first pinion and first toothed wheel. This is necessary to avoid the possibility of the first pinion and the first toothed wheel meshing with or obstructing one another, and necessarily results in an enlargement of the spacing between the axes.
A further disadvantage of this known proposal is that the forces acting on the teeth of the intermediate wheel, resulting from the meshing with the first pinion and the first gear wheel, are essentially in opposite directions, so that the teeth of the intermediate wheel are required to yield in opposite directions. This factor dictates that the toothing must necessarily be broad, with corresponding increase in the width of the drive.
The above-discussed disadvantages arise particularly when the known type of double-oblique-toothed two-stage spur wheel drive is used to drive a ship, since in such an environment lengths and widths of the drive are of particular significance.